High-frequency apparatus



April 13, 1948. T. J. BOERNER ETAL 2,439,682 v I HIGHFREQUENGY APPARATUS Original Filed June i7, l1945 4 Sheets-Sheet 1 bnf u k www l' do xvbx hiwx s April 13, 1948. 1'. J. B'OERNER Erm. 2,439,682

' HIGHFRE(,`2UFNCY APPARATS Original Filed June l',v 1943 4 Sheefs-Sheet 2 /Nl/E/v Top5' eouL unborn l A TTo/PNE Y April 135 1948- T. J. BoERNER ETAL. 2,439,682

HIGH-FREQUENCY APARATU-S A.

Original Filed Jun 17, 1943 4 Sliee'cs--Sheetl 3 April 13, 1948.

T. J. Bbl-:RNER l-rrm.` 2,439,682

HIGHFREQUENCY APPARATUS I Original Filed June 17,(1943 4 Sheets-Sheet 4 er with wide non-critical points of overlap. Further adjustment in the circuits may be made by means of the taps on coil ILIB and by changing the position and couplingof a short-circuited turn ILI6A with respect to ther turns of coil ILI6.

The grids ofthe power amplifier tubes are subjected to biasing action through the action of a common resistor IRIUII and the further resistors IRIUUA. As indicated, one ofthe lattern is A connected in series with the grid of tube IV!!l and the other in series with the Vgrid of the other tube IVIO of the power amplier. -Also,fit will be noted that chokes IL50 and IL50A and radio frequency by-pass condenser ICI3IJ have been provided in the grid circuit of the power amplier stage. The grid circuitas'des'cribed provides balanced grid currents over the entire range of frequencies employed.

Neutralizing condensers ICIIl'I and ICIIIG, which Will be describedin greater detail hereinafter, are provided for thepower ampliilerl tubes IV9 and IVIO. Also, as vwill bedescribed more fully hereinafter, the tank'circuit of the power amplifier comprises the inductance ILI', tuning condenser ICI I2, short-circuiting strap ySB, condenser ICI23, by-passing .condenser I Cl24 and choke IL56.

The loading or output circuit, which also will be described more fully hereinafter, comprises the inductor IL52, turning condenser ICI I4 and ilXed angular position of motor IA20 isindicated on a tuning indicator IMI3 which is inefiect a voltmeter, the voltage of which depends upon the position of tap 40B upon potentiometer IR4`3. The tap 40B is moved along the potentiometer IR43 by the action of motor IAZIl'. `Inother words, motor IA29 simultaneously variesqcondensers ICIilt and ICIU'I andthe positionof tap 49B along potentiometer [15243.V i L Similarly, reversible `driving motors IA2V3, IA2I, IA24 and IA25, switches 'IS9,' ISS, ISIII and ISII, limiting switchesv ISI6, ISI'I, ISI4, ISI5, ESIS), ISZD and ISZI, and indicators IMI5, IMI4, IMIS and IMII are provided for adjusting and indicatingy the adjustment of condensers JICIIZ, coupling between inductors IL5I`and IL52` and condenser ICI I4. Supply voltage for the tuning indicating system is derived Vfrom the rectier arrangement IA30. Motor driving power is furnished through leadsl IB and 2A. The power supply to these leads may be,.for example, 220 volts 60 cycles A. C. current.`

The limit switches, such as ISI2 and ISI 3, may be operated by cams, in turnoperated or driven by reduction gearing coupled to the motor IAZU, so that after a given number of 'revolutions in one direction, limit switch ISI2 `willvbe opened and after a givennumber ofrevolutions in the other direction limit switch ISI3 will be opened. Similarly, the potentiometer and tap arrangement 1R43 and 40B may be controlled by reduction gearing also coupled to the motor IAZII, the tap being in contact with and moved over a circularly shaped potentiometer. Similar comments are applicable to the other limit switches and potentiometers controlling the tuning indicators TI. The

4 latter are provided with by-passing condensers IC'I5 to IC"I9 inclusive.

A preferred electrical and mechanical arrangement of the various parts of the power amplier systemand output circuit areshown in Figures 2 to 4 inclusive.

As briefly stated before, Figure 2 is a side elevational view of the power amplier assembly comprising tubes IV9 and IVII); Figure 3 is a front elevational view of Figure 2; and Figure 4 is a 'v sectional vieWof-Figure 2.l

Turning to Figure `3, radio frequency excitation from the driver stage is fed to the grids of the power amplifier tubes IV9 and IVIO at the grid input terminals 33 and 83. Two leads to each Agrid areprovided which are connected together y and to external circuits at 54.

The neutralizing condensers ICIU'I and |0106 `of Figure 1 are illustrated in Figures 2 and 3 and are seen to comprise rounded or rectangular plates 56 Adirectly attached to the tube anodes by means of brackets 56A and-56B. f The variable plates of the neutralizing condensers are plates 59, .60 each of which is of U-shape, so as to partiallyi surround each of tubes V9 and VI il. These U-shaped plates 59, 50, xed together by insulating strip 59A, are simultaneously rotated on hinges 54, 64A by the operation of ther motor IA29. This ,follows sincerotation of motor IA20 is translated into movement of condenser plates 59 and 60 by means of drum DI, cable 91 and insulating supporting anchors 63, 63A appropriately attached to the plates 59,60. i l Y Individual adjustment of the neutralizingcondensers may be made by adjustment of the wing nuts |54, whereby the condenser platesY 56 may each be independently adjusted with respect` to the simultaneously moved condenser plates 59. 60. This can be done since the brackets 56A and, 56B are slotted so that the condenser plates 55, may be moved axially along and fastened inany desired position with respect' to the vacuum tubes V9 and VII) and, of course, with respectgtoY the movable condenser plate combination ,59, 6 0,

4The tank circuit condenser IC-I I2 of Figure 1 is also illustrated in Figures V2 and 3. This condenser, as illustrated in the latter `ilgures, includes the edge rounded, substantially rectangular plates 46 and Alf Plate 46 is independently adjustable with reference to the movable plate 35, andalso with respect to tube V9 by means oihinge 49, and the slotted bracket and wing nut construction I54. By a similar arrangement of V parts condenser plate 41 is made independently adjustable with reference to movable plate 35 and vacuumvtube VIII. Y

Plate 35 is adjusted by rotation of motor` IA23 through gear reductionV mechanism withinthe motor casing and bracket cam and s lottdapparatus. The cam and slot apparatus is shown more clearly in Figure. 2 at 36 and 3'! Cooling water is fed to the anodes ofthe vacuum tubes through the insulating coils 24, 25 which provide for direct current insulation from ground. The cooling water is also fed` and removed through the straight sections of insulating pipe 20 and 2I. 4The' latter oier Vhighimpedar'ice to and eectively insulate the tube plates from ground fior radio frequency currentsl v As shown in Figures 2 and 4, the inductiveportion IL5I of the tunable-tank circuitof Figure 1 consists of metallic tubing 339, v34|) and 3 4I`. This tubing 3 39, 340 and 34| is Yremovably iliced t the nodes by means of the Wingnut operated flanges Alscrtheinductcrffl115i: olligurermayinclude f omcertainfirequencyfrangesfportions of-the vertically-,movableinductors 325; .325A, .ofz;Figuresf2 Thisfmovabler-inductor A"portion t 32,5;` 325A issllppm'tednbyrstandzoiinsulators;YI 46;,upon an edgcz-roundedI rectangular metallicrplate 32| which: is fedtwith z platejfvoltage :through ,conductivae,=.:strap.Y 133:-, (Fig;.,2,., Meta1ipla-tef32 Iiimturn is. insulatingly.` supported fromiapgrounded me.- tallicrrplatelrby means; OadditiOnaIzstand-o insulators 3l Grounded fplatey 3f] has attached.z thereto threaded-spindles .-3 I 9 :cooperatingawithi internally threaded: sprockets `3 I 3;.im turnsupported-xr by grounded metallic;AA pedestals 13,:I 0i., Motori' YIA2'I drives suitable: gear; reducing" mechanismy within the motor casing and the latter throughbevel gear;:mechanism;BGl\/Land.sprocket S drives chain 326. Chain- 32 6': causes simultaneous operation of all of the sprockets 3I3, resulting in movement of the entire assembly upwardly ordownwardly. ,assembly `includes.. ground. plate 3 I 5, anode or B voltage plate 32I, and the apparatus supported by rectangular `plate V,32I which apparatus includes inductor 325; condenser I'CI23 and choke coiltIL. The directionmofrotation of, `motor IAM and, hence, the direction of movementou the :assembly depends `uponthe. .position to which swatch ISIlrtofA Figure is ,thrown. Movement r of the assembly changes v the inductancel between thetbottomturn 32,5, 325A Vandfthe upper turn 333g 3.40 Whhisxed in position and clamped as illustrated at 5I to the anodes of vacuum tubes V9 and VIII. In this Way, the total tank inductance is changed, decreasing as the assembly is lowered and increasing as it is raised and the turns 339, 340 and 325, 325A brought closer together. This change in inductance gives one control of the tuning on the tank circuit comprising IL5I of Figure 1. Another control on or adjustment of this tuning has already been mentioned,"` namely, adjustment of ICI I2 under control of switch IS9 of Figure 1 and reversible motor IA23.

A more detailed description of the plate tank circuit inductance will be had by referring to Figures 5, 6, 7 and 8 and the description thereof in our patent application Serial #491,164 iled June 17, 1943, now United States Patent No. 2,412,314, granted December 10, 1946. `The latter figures of our patent application diagrammatically illustrate connections and adjustments for various frequency bands.

Referring to Figure 2, it will be found that the condenser plate arrangement 3I5, 32| improves stability and tends to lessen the setting up olf parasitic oscillations. The plate voltage lead |83 is grounded for radio frequency currents by means of the condenser ICI24, as illustrated more clearly in Figure 2.

The inductance of the output circuit IL52 of Figure 1 consists of a portion of the hairpin inductor L52 or L52A of Figures 4 and 2. The coil of the larger conductor size L52 is employed for the higher frequency range such as, for example, from 15 to 22 mc. The hairpins L52 and L52A which may, for example, consist respectively of one inch and two inch copper pipe, are selectively connected into circuit by the flexible connecting straps 382. As shown, L52 is connected into circuit. The fixed condenser tank ICI I5 to ICI 22 inclusive of Figure 1 is similarly illustrated in Figures 2 and 4.

The variable plates of condenser IC I I4 of Figure 1 are illustrated in Figure 4 at 310 and 310A,

each? cc'nsistingv` al substantiallyj-i.` rectangular metallici platehaving:` rounded; corners and rounded edges: .c These movable condenser; plates are provided ewithmetallic: dishpan supports 37 I, `in turn supporting stand-om insulators f 3,391 ex'- tendingthrough roundedV `olffperf orations s through the; .movable plates-` 310i andrS'lIlAa. In this @way electric istress on the stand-loir; insulators: is reduced:y While at.y the;` saine,l` time permitting: the movable plates ,3 I 0 anz31 IlA-- to 1 betbrought closer to the grounded plate 358. Rectangular: grounded plate ,358 extends, across` andi istherebyrcapacitively coupled to both of the movable platesr3'lll and 310A. This is :clear :from an inspection of Figure 4. i l

Referring again to Figure 2, bymeans of motor IA25` and its reducing ,.gearingdriving. the sprocket: S'PIcha-in.` 326A and` the,H remaining sprockets SP2, SP3; SP4, SP5 and SP5," the latter three `being directlynbehind SPI, 1SP21'.and-SP3, condenser plates--S'Iaud 310A are adjusted Yin a vertical direction. The sprocketsqare` supported `upon the pedestals365` which inturnrare fastened tothe condenser plate-35E. The sprockets are internally threaded and the;4 threads) thereof engage the threads-,on the spindles 361; 338 and 358A thereby causing, `movement` of` the movable plates 37@ `and 310A .withfrespect toxthercommon condenser plate .358 in, a direction::perpendicular tothe planes of the condensenplates; `.From what has, been said, it, shouldfbe clear; that the spindle, sprocket and. motor. mechanisms. IA25, SPI, 363, etc., is similars-tofthe spindle; chain and sprocket driving mechanism described for moving the plates SI5, 32| and the apparatus supported thereby.

In a similar Way motor IA24 operates the sprocket, chain and spindle mechanism 3I3B,

321B, 353B and 354B whereby the entire assembly of inductor unit IL52 and condenser ICI I 4 is moved in a Vertical direction. Hence, operation of motor IA25 controls the tuning of the output circuit independently of the coupling to the tank circuit, and operati-on of motor IA24 may be used to control the coupling of the output circuit to the plate circuit of the power amplier Without altering the tuning of the output circuit comprising ICI I4. It is to be noted that movement of the output assembly also includes oondenser ICII5 up to and including ICI22.

The output from the output circuit is taken through exible conducting straps 38| and 38IA to suitable terminals supported upon insulators 385. From the latter terminal a conductive strap CS3 brings the amplied high frequency Waves to suitable insulatingly supported Ioutput terminals 35I and 35IA, as shown in both FiguresZ and 4.

As explained in-connection with Figure 1, the various electric motors are mechanically coupled by reduction gearing and other mechanical instrumentalities to change tuning of condensers, coupling, etc. Also, additional gearing is provided Whereby each mo-tor mechanically drives the movable arm of e, potentiometer which may -be arranged in the form of a circle. For example, as shown in Figure 1, motor IA2I drives rheostat arm IIIB of potentiometer IRM. The potentiometer arrangement is illustrated somewhat schematically to the left of motor IA2I in Figure 2 at point IRM. Similarly, for example, the potentiometer associated with motor IA24 is illustrated at IRIIB in the upper part of Figure 2, and the potentiometer associated with electric motor IA25 is illustrated at I R41, also in Figure 2.

Other parts of the apparatus illustrated in Figures 2, and ishld be self-evident to those skilled in the art, for example, the steel frame- Workof the system and filament transformers T20 and T21, blower motor AI8 (Fig. 3-top) filament ley-passing condensers 10108, 10109, etc., and ICI 25 of Figure 1. Also, it is to be noted that the grid chokes IL50 and IL50A of Figure 1 are illustrated in Figure 3, as is also condenser 10130. The stand-olf insulators with corona shields 9 for the tube sockets I0 and 11 are illustrated at 8 in Fiefure 2. i l

Having thus described our invention, what we claim is: Y Y Y 1. In high frequency apparatus, a pair of vacuum tubes each having an anode and supported so as to have their longitudinal axes substantially parallel, e, pair of condenser plates hingedly vmounted upon the anode structures of said tubes,

a slotted bracket and a screw threaded nut forxing the position of said hinged plates in desired position with reference to said anode str-uctures, a third condenser plate electrically cooperating with said pair of hinged condenser plates, and motor driven camv mechanism for controlling the positioning of said third plate with respect` to said pair of condenser plates hingedly mounted upon said anode structures.

2. Apparatus as i claimed in the preceding claim, characterized by the fact that each of said condenser plates has a capacitive surface which is plane, being further characterized by the fact that said condenser plates have rounded oi edges, being further characterized by the fact that said third condenser plate is mounted so astobe movable about a xed point and is operated by cam mechanism at another point spaced therefrom.` 3. In high frequency apparatus, a pair of vac:-V uum tubes each having an anode and supported so as to have their longitudinal axes substantially parallel, a pair of condenser plates hingedly mounted upon the anode structures of said tubes, a screw threaded nut for xing the position of said hinged plates in desired position with. reference to said anode structures, a third condenser plate electrically cooperating with said pair of hinged condenser plates, and motor driven cam mechanism for controlling the positioning of said third plate with respect to said pair of condenser plates hingedly mounted upon said anode structures.

THOMAS JAMES BOERNER. JOHN W. SANBORN.VV

REFERENCES CI'II)i The following references are of record linthe le of this patent:

UNITED STATES PATENTS 2,346,929 Litton Apr. 18, `1944 

